I'd like to see a photo too if possible Hayjud. After reading your description, the first type of lamp that popped into my mind were those popular during the Arts & Craft movement. The shell "type" inserts may possibly be mica. If they are, I would not suggest that you take them out. Mica is flexible and brittle.

I agree with lazygarden. I would not give the lamp a "polishing" but I would replace the wiring (saving all parts).

I also second NOT cleaning the copper off until you have the lamp appraised - I recall a lamp (from the arts and crafts period) on The Antiques Road Show - the new owner polished all the old patina off til it gleamed - and also lost several thousands of dollars in value because of it.
I would also take the lamp to a 'professional' to rewire - if it is a valuable lamp - it probably would be worthwhile to use a similar type of electrical cord - i.e. fabric covered, etc., keeping with the original style.

Another who says don't polish it....Perhaps the inserts are capiz shell.....in which case it wouldn't be as old as if it were mica.
Post a picture if you can....and be sure to let us know what you find out.....and be aware that every appraiser doesn't know everything about what they see. I would look for an identification rather than appraisal...unless you want to sell it.
Linda C

Yipes! Please correct my original reply regarding the mica. Do NOT take them out. So sorry...I should have proofed better.

Thank you all for that valuable advise!

I was assuming that a good polishing would be the way to go.
I found a lamp similar to this one at "Go Antiques." It's priced at $1,595.00! Wow I bet Dh's grabby sis had no idea, or she would have grabbed it!
Here are some pictures of it:

This is the base and one of the sockets have been replaced. We don't have the original one.
This is the shade:

I can feel a greasy film on the inserts. They feel fairly thick and like a glass. It seems to be strong, and certainly not flexible.
Hayjud

We put it back together and I have a picture of the whole lamp.

The picture looks brighter then it actually does.

So you all think the best way to clean it is to just buff with a soft cloth. Is that green suposed to be there? I think the green is ugly!
Hayjud

Judy, I'd wager it's worth every penny and more of the $1,595 one that is similar even with the socket that has been changed out. I still think it's a lamp from the Arts & Craft period (turn of the century) and most likely (after seeing the shade) it's slag. I think it's gorgeous, green included, and don't you dare clean it now that we've seen it. BTW...did I mention, I crave that lamp? That's just too bad about Dh's sis. LOL

Anyway...clean the slag with a damp cloth. It's not as fragile as mica. Have you found any markings on the metal? Look around the rim and on the underside.

I hope you're going to keep it. Really...it's simply marvelous.

WOW!!!!....For sure a slag glass honey from about 1910 or so.....
Have it rewired if you want to....but no polishing!!!
It's fabulous!!!
And....if you take it somewhere to be rewired....make sure they know not to clean it!...
A bit of rubbing alcohol on a cotton ball will clean the glass......don't use Windex as it contains ammonia and will ruin the patina on the copper ( which is likely bronze)
Linda C

WOW! Art Nouveau (the swirly curly ornament distinguishes it form the simpler, more angular "Arts and Crafts" stuff form the same tume period) from 1895-1915 or so, with "slag glass" or other hand-blown glass shades. (might be called "opal glass" by some.

Check the shade and base carefully, with a magnifying glass, for signatures or makers marks.

The green is "patina" and it's supposed to be there. Just wash off the grime with a mild detergent, rinse and dry.

Of course ... if you think it's an ugly green thing, I could give it a good home :)

Lazygardens, I thought you were meaning somebody by the name of ART, who's last name was Nouveau! LOL I don't know anything about antiques!

I have not been able to find any markings, but I'll try again in the bright daylight.

LOL - LKG and lazy, I'm not looking for a new home for it, but you can be my friend any time!
This will be staying in our family - BUT, we have 3 children!!!

When I took the shade off again to look for markings, I noticed the inside of the center doesn't have the same copper color. I'll let you know if I find a marking.
Hayjud

It's beautiful & very similar to a lamp given to my grandparents. Their house burned down around 1900 & they built another in the same spot. The new house had electricity, so their church gave them the lamp as a housewarming gift. My brother has it now. It's very heavy brass, with 6 caramel slag glass panels with delicate filigree. Ditto the comments about rewiring, not cleaning & craving. Enjoy!